This is all just my opinion and I am not a medical doctor. I've just dealt with, experimented with (on myself), and made a study of, dehydration.
Sounds like she is chronically dehydrated. I suspect that many stomach problems with MMS are due to dehydration - sometimes from the diarrhea created by the illness and sometimes from the chronic state of dehydration that most people keep their bodies in - and not taking enough water with a dose.
There is a re-hydrating solution you can make - with instructions - at rehydrate.org. The site is geared more toward global problems with diarrhea but diarrhea is treated as a cause of dehydration, whereas constipation - and quite possibly the pneumonia - would be considered a symptom.
TAKE IT SLOW. Don't have a dehydrated person try to re-hydrate, all at once.
I'd skip the MMS until she's re-hydrated as dehydration increases the acidity of the blood and acid seemss to be an MMS target.
If she is chronically dehydrated, then the body is having to deal with, not only the rationing of water, but also low blood volume and as it steals water from other parts of the body (namely, the colon) to keep the lungs (the most vital organ, in emergency-dehydrated mode) hydrated to deal with contaminants, the low blood volume can't keep up. And to top it off, all of the body's work, including all of this extra work, is faciliated by - you guessed it - water. So it is not only having to make water to use but it is also having to make water to make water.
Avoid caffeine. It is believed that 8 ounces of caffeinated beverage requires 12 ounces of water to deal with. But I don't think the body deals with it properly when it is in water rationing mode. It doesn't appear to be very high on its list of priorities, in that state. God only knows where un-dealt-with caffeine goes or what it does.
Water is the most vital element, physiologically. It's what makes blood bloody, it's what keeps your internal organs in their state of being organs - as opposed to dog treats - and it's what carries all of the information the body needs to keep you alive. Just keeping you upright and conscious is a heavy duty job when you are dehydrated.
You know that little dizzy feeling one gets upon standing? That's accompanied by an increase in blood pressure and heart rate as your body tries to pump enough of that low blood volume to your head so that you don't pass out, fall down and get eaten by a lion. It's a basic circulatory function of a mammalian body that walks with its head so far above its heart and that is in emergency water rationing mode i.e. dehydrated.
Anyway, re-hydrating would also take care of the ulcer, but if it didn't do it quick enough to suit, and she were well on her way to being re-hydrated, I would use a very low dose with plenty plain cold water to keep as much distance as possible between the CLO2 and its targets. The cold water will allow a small amount to release in the stomach and clean up the ulcer but keep more in solution to take to the bloodstream as the water (on an empty stomach) is warmed and assimilated by the body. Who knows what it is doing with CLO2 in solution when it is busy trying to make its own water! If it is ignoring it and letting it roam around as it pleases, as it appears to do with caffeine...who knows?
Again, TAKE IT SLOW! Don't try to re-hydrate all at once, it can't be done. The body is in "emergency" mode and probably has been, for quite some time. She may already be sleeping sitting up or in an inclined position but, if not, do that, as well. Have her avoid lying flat, as on a flat bed. You can raise the head end of the bed about 6 inches. Sleeping on an incline is actually good for you. It increases the amount of time the body is in a state of actively circulating its fluids. Lying flat, slows it all way down and adds another condition the body must deal with. It is a little known fact that hospitals will, in rare cases, lie severely ill or wounded patients flat to help facilitate death.
Anyway, the body assimilates water on an empty stomach completely differently than food. It uses it, right away, in the systems it has been sending rationed water to, then sends it to the systems it has been stealing from and then, after all of that, it uses it to make repairs. It can take quite a while in a case of chronic dehydration but she'll feel much better during the process.
You can't rush a dehydrated body by flooding it with water. It is WAY too busy in its emergency rationing state to deal the shock of a deluge. Gradually increase her intake of water on an empty stomach - and that's water, not "fluids". She can also take juice to help "water" the digestive system, but not with the water.
Juice and other fluids are assimilated as food, in the digestive tract and distilling it down to get water that the body wasn't getting otherwise will stop if she is re-hydrating, so that more is available for the colon. Stealing water from the colon is a completely different and laborious process (that ALSO requires water to facilitate) than assimilating water on an empty stomach. I'm not a big juice drinker but I like grape juice so I use Welch's 100% grape juice. The point being that if the body is getting water, on an empty stomach (easily assimilated), then it won't have to make its own by over-distilling (diSTEALING) the fluids that actually belong to the colon and re-hydration won't take as long.
Your body can handle just about anything this planet can throw at it, IF it is properly hydrated. Properly hydrated, it could even, theoretically, handle "bad" water if one didn't stop drinking it because it was "bad", thereby becoming dehydrated.
The body is a magnificent mechanism, left to its own devices. The next time your poky old brain assumes you're hungry, try drinking a glass of water down and see what happens. I have a theory that over-eating AND some of the emotional issues associated with it are actually symptoms of dehydration and that some "hungry feelings" are actually over-thought. Acidic blood in the brain? That's gotta be causing some misfiring, or over-firing or otherwise wacky sparks, neurologically-speaking, in my opinion. don't ya reckon?